(1) Field of the Invention
The invention relates to a valve and a method for producing a valve having a valve seat with a valve seating element. More particularly the novel valve and method for producing the valve includes a stamped out valve seating surface.
(2) Description of Related Art Including Information Disclosed Under 37 C.F.R. 1.97 and 1.98
At present, a wide variety of valves are commercially available. For example, electromagnetic valves, in particular bistable valves, exist and can be used in various applications, for example in fluid circuits of domestic appliances such as refrigerators or for steam expansion for drinks machines, such as coffee machines for example, but also another areas such as in the area of analytics or measuring technology.
In most application areas, such as for instance the application area of domestic appliances, valves which are of a compact design are preferred that can also be produced and fitted with as little effort as possible. To satisfy these requirements, various developments have already become known (cf. DE 199 14 972 A1 or WO 03/071 176 A1).
Known valves have, inter alia, a valve seat, which are sealed by a valve body to ensure the function of the valve. For example in the case of ball valves, a spherical valve seat is accordingly required. For sealing the valve seat, an elastomer seal or the like may be used for example.
In addition, metallic seals may also be used in certain applications. The use of correspondingly metallic, spherical sealing seats requires very precise and uncontaminated production and fitting of the valve. Corresponding valve seats, in particular in the case of valves with armatures, are often hardened after turning on a lathe, producing a certain hardening distortion. In the case of some certain valves, the pole shoe comprising the valve seat may be covered with copper or the like after hardening, so that subsequent soldering of the pole shoe can be advantageously realized. Even with this copper coating, inaccuracies with respect to the form of the valve seat can occur, and may lead to the valve leaking during operation.
In addition, particles of dirt can contaminate the valve seat both during the production of the valve seat and during the fitting of the valve, which in turn can lead to the valve seat leaking during operation.
The known prior art also includes Hopf, et al. U.S. Pat. No. 6,173,914 uncovered by the U.S. Patent Office during the prosecution of parent U.S. application Ser. No. 11/013,880. Hopf, et al. U.S. Pat. No. 6,173,914 pertains to a foil strip layered valve seat having at least two sheet metal layers that are first provided with openings of desired geometries at Station B (FIG. 2 of Hopf, et al. U.S. Pat. No. 6,173,914) which foil strip layers with openings are accurately positioned and pressed together at Station D. The band of foil strip layers is then processed by punching the layered foil strip with either a deep drawing tool or first punched and then cupping after punching with a deep drawing tool.
Hopf, et al. U.S. Pat. No. 6,173,914 relates to a layered valve seat having an opening that is equal to or greater than the thickness of the foil layer. See prior art FIGS. PA1, PA2 and PA3. The ratio of thickness T of the metal sheet to the width of the opening D provides a T/D ratio that is either 1 or a fraction less than 1.
The stamping pressure of the deep drawing tool of Hopf, et al. U.S. Pat. No. 6,173,199 is not specified. The stamping pressure as would be recognized by one skilled in the art would be at a pressure less than a pressure that would deform openings 23 and 23a since such a deformation would impart an undesirable inconsistency in the spray flow characteristics to the spray discharge openings 23(c) FIGS. PA2 and PA3. In addition since foil metal layer strips are used in Hopf, et al. U.S. Pat. No. 6,173,914 all stamping pressures employed will be distributed through the layers and cushioned by the weld, adhesive bonding or other known methods for joining the foil strips together.
The invention in contrast employs a solid unitary metallic body that is not a metal foil but instead a pole shoe made of high grade steel. The unitary metallic body has a thickness T and a valve bore with a diameter D so that the ratio of T/D is never a fraction and always greater than 1 and preferably about 2 which provides an identifiable bulge in the valve bore. The solid unitary metallic body also includes an annular web which is deformed into a stamp deformed sealing surface at the same time the valve bore D is deformed.
The pole shoe also includes an annular stop surface for mating with a corresponding stop surface on the stamping tool which forms a seat for a magnet.
The object of the invention is to provide a valve and a method for producing a valve with which the aforementioned disadvantages of the prior art are reduced or avoided.